> ## Documentation Index
> Fetch the complete documentation index at: https://voltaire.tevm.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# Fr

> Auto-generated API documentation

[**@tevm/voltaire**](../../../index.mdx)

***

[@tevm/voltaire](../../../index.mdx) / [crypto/Bls12381](../index.mdx) / Fr

# Fr

## Functions

### isValid()

> **isValid**(`scalar`): `boolean`

Defined in: [src/crypto/Bls12381/Fr/isValid.js:9](https://github.com/evmts/voltaire/blob/bd6ec34405c15ad8cd51d11579d495dc53813482/src/crypto/Bls12381/Fr/isValid.js#L9)

Check if a scalar is valid (in the range \[0, r-1])

#### Parameters

##### scalar

`bigint`

Scalar to check

#### Returns

`boolean`

True if valid

***

### mod()

> **mod**(`a`): `bigint`

Defined in: [src/crypto/Bls12381/Fr/mod.js:9](https://github.com/evmts/voltaire/blob/bd6ec34405c15ad8cd51d11579d495dc53813482/src/crypto/Bls12381/Fr/mod.js#L9)

Reduce a bigint modulo the scalar field order r

#### Parameters

##### a

`bigint`

Value to reduce

#### Returns

`bigint`

Value reduced to \[0, r-1]